What is Denial of Service?
DoS attacks make the victim computer(s) reset or consume its resources such that it can no longer provide its intended service, or it can obstruct the communication media between the intended users and the victim in such that they can no longer communicate adequately.
Distributed denial of service (DDoS) attacks do the same thing, but incorporate the use of multiple sources to attack the victim. Flooding and internet site with requests, overloading a web server with data, and spamming an email box with enormous amounts of email can be attempted with normal DoS attacks, but with today’s understanding and countermeasures, normal DoS attacks will almost never be successful. This is the reason DDoS was invented; if one computer can’t be successful, thousands working together can! CERT gives a good explanation of DDoS here.
Is it ethical?
Since DoS attacks are illegal, the first inclination would be to say “No, it is not ethical.” Deontologists would agree because the act of doing something illegal is unethical, no matter what the consequences may be. But some utilitarianists may disagree.
If you were to launch a DDoS attack on a child pornography site, would the ends justify the means and thus become ethical? A utilitarian opponent of child pornography would say “yes”. What about if you launched a DDoS attack on an opposing political party’s website? What if that political party was the Nazi party or a government that you may believe is evil? The point is that there is a very gray area when it comes to utilitarian ethics concerning DDoS attacks. They can be used for “good”, but who’s “good” are we talking about?
Protecting Against DDoS
Since DDoS uses many computers at once to launch its attack, the best way to protect against against DDoS attacks is to stop it at its source, the individual computers. Being diligent in the use of anti-virus, anti-spyware, firewalls, and simple security measures would stop most hackers from being able to use a computer for a DDoS attack. But, just in case the entire world doesn't suddenly start to secure their own computers, the sites and services of companies need to protect themselves. Using updated hardware and software and learning how to protect yourself (see the links on the index page) will stop most attacks from succeeding. But remember that hackers are very resourceful,
they will continue to find ways to succeed, and those being attacked need to continue to find better ways to protect themselves from possible attack.